Method of balloon construction



Jan. 12, 1954 F, MERE ET AL 2,666,006

METHOD OF BALLOQN CONSTRUCTION 7 Filed April 2, 1948 8 Shet's-Sheet l 8 INVE/VTORS FRANK J. LAMERE KERMIT F. JOHNSON OTTO C. WINZEN BY P. ATTORNEY 1 an- 1954 F. J. LA MERE ET AL METHOD OF BALLOON CONSTRUCTION 8 Sheets-Sheet 2 Filed April 2, 1948 INVENTOR S FRANK J. LAMERE. KERMIT. F. JOHNSON OTTO C. WINZEN BY 0 nmswr Jan. 12, 1954 E ET AL 2,666,006

METHOD OF BALLOQN CONSTRUCTION v Filed April 2, 1948 8 SheetS-Sheet s 59 63 53:54 6

V/I/IlZl/IIIII/Id INi/ENTORS 8o FRANK J. LAMERE KERMIT F. JOHNSON 0TTO C. WINZEN BY W A T TORNE Y Jan- 12, J. LA ET AL METHOD OF BALLOON CONSTRUCTION Filed April 2, 1948 8 Sheets-Sheet 4 FIG I l INVENTORS FRANK J LAMERE KERMIT F. JOHNSON OTTO c. WI[\(ZEN w BY M ATTORNEY 1954 F. J. LA MERE ET AL 2, 66,

METHOD OF BALLOON CONSTRUCTION Filed April 2, 1948 8 Sheets-Sheet 5 FIG. l6

INVENTOHSw FRANK J. LAMERE KERMIT F JOHN OTTO C. W|NZ E ATTORNEY 1954 F. J. LA MERE ET AL 2,666,

METHOD OF BALLOON CONSTRUCTION Filed April 2, 1948 8 Sheets-Sheet 6 FIG. 20

FRANK J. LA MERE KERMIT F JOHNSON OTTO C. WINZEN A TTORNE Y n- 1954 F. J. LA MERE ETAL METHOD OF BALLOON CONSTRUCTION 8 Sheets-Sheet 7 Filed April 2, 1948 INVENTORS FRANK J. LAMERE KERMIT F JOHNSON OTTO c. WINZEN a g ATTORNEY 1954 F. J. LA MERE ET AL 2,666,006

METHOD OF BALLOON CONSTRUCTION Filed April 2, 1948 8 Sheets-Sheet 8 FIG. 22

INVENTORS FRANK J. LA MERE KERMIT F. JOHNSON OTTO C. WINZEN A T TORNE, .Y

Patented Jan. 12, 1954 UNITED STATES PATENT OFFICE METHOD OF BALLOON CONSTRUCTION Frank J. La Mere, Kermit F. Johnson, andOtto C. Winzen, Minneapolis, Minn., assignors to General-Mills,lnc., a corporation of Delaware Application April 2, 1948, Serial No. 18,585

1501aims. '1

This application relates to a method and apparatus for construction of high-altitude -bal- Icons.

One object of the present invention is the provision of an improved method for manufacture of balloons.

Another object is the provision of apparatus with which the improved method of construction may be carried out.

A further object is to provide a balloon table on which the material may be laid out and assembled with a minimum of handling.

Still another object is the provision of such a table in which an edge of the table is shaped to correspond to the shape of the gore edges in such a balloon.

A still further object is to provide such a table in which a cutting and welding unit is mounted for movement along one edge of the'table to trim the balloon material to the desired shape and join adjacent gores of the material together.

An additional object is the provision of a ballloon assembly table having at least one edge corresponding in shape to the gores of the finished balloon and having a central depression for accommodation of a portion of the gores during the assembly operation.

Another object is to provide an improved templet for trimming the top or apex of the balloon and assembling a suitable cap at said apex.

Other objects and advantages will :be apparent from the following specification in which a preferred embodiment of the invention :is described.

in the drawings which form a part of this application, and in which like reference characters indicate like parts,

Figure 1 is a perspective view of-a balloon made by the present method and apparatus.

2 is a perspective view of a balloon-assemblytable according to the present invention.

Fig. 3 is a view similar to Fig. 2 with certain portions omitted for clearness and with a sheet of balloon material in position on the table.

Fig. 4- is a perspective view of the apex end-of the table of Fig. 3 taken from the section linedi of figure.

5 is a schematic view. partially in section, showing the welding unit which forms :a part of theballoonassemblytable.

Fig. 6 a partial sectional view showing the ont of the first .two sheets of gore material as ssembly operation is started.

7 is a similar partial view showing the position the weld line prior to taping of the gore seam.

Fig. 8 is a partial perspective view which illustrates the start of the taping operation at the apex of the balloon.

Fig. 9 is a View similar to Fig. 8 with the taping operation at a more advanced stage.

Fig. 10 is a partial perspective view showing details of the completion of the taping operation. at the bottom of the balloon.

Fig. 11 is a schematic sectional view showing the arrangement of the gores and gore material prior to making the second gore seam in the series.

Fig. 12 is a View similar to Fig. 11 showing the gores after a number of seams have been joined.

Fig. 13 is a view similar to Fig. 11 after all the gore seams except the final seam have been made.

Fig. 14 is a view similar to Fig. 11 showing the method of laying out the material for the final joint between the first and last gores.

Fig. '15 is a similar view which illustrates the final taping operation of the last seam.

Fig. 16 is perspective view of the assembled gores with an inflationtube in position within the apparatus in which two assembly tables are provided, and

Fig. '23 is a sectional view on the line 23-23 of Fig. 22.

With reference to Fig. 1 the balloon for which the present method of assembly and apparatus are designed is composed of a series of vertically extending gores 25 made of suitable gas-proof material. These gores are joined to each other'at their vertical edges 26 to form the main body of the balloon. A suitable cap 2? i provided to seal the apex of the balloon. The lower ends 01 the gores .25 are fastened to a load ring as from which the desired load may be suspended by means of suitable load lines 29.

The assembly of such-a balloon involves essentially two operations, namely the assembly of the longitudinal "gores which form the main body of the balloon and the application of the cap at the apex of said gores. These two steps and the apparatus for carrying them out are described separately below.

Assembly of the gores To facilitate the cutting and joining of the gores to each other we have provided a balloon assembly table having a flat upper surface designated generally as 3!. This table surface 31 is mounted on any suitable support 32. One edge 33 (Fig. 4) of the table is perfectly straight and is used to align one edge of the sheet of gore material. The opposite edge 34 of the table tapers at each end to correspond to the desired shape of the edge of an individual gore of the balloon. Thus edge 34 will serve as a guide or pattern for the trimming of the gore material and the joining of adjacent gores.

An index line 35 is provided on the top of table 3! to indicate the line of the opposite edge of each'gore. Thus the shape of a single gore is defined on the one side by table edge 34 and on the other side by index line 35. Since the gores are symmetrical, the edge 34 and line 35 will taper symmetrically toward each end of the table corresponding to the apex and bottom of the balloon gores.

The intermediate portion of table 3! between edge 34 and index line 35 is recessed or depressed as shown in Fig. 4. This recessed portion has a bottom 38 and side walls 36 and 3'! which form in effect a trough extending longitudinally of the table. The depth of this trough or recess is sufficient to accommodate the assembled gores as described below.

On one side of table 3! corresponding to edge 34 tracks 40 and 45 are connected to frame 32. These tracks are designed to support the wheels or rollers 42 and 63 respectively of a welding unit 44. An electric conducting strip 45 on the bottom of rail 40 is suitably insulated from said rail and cooperates with a contact roller 46 on the welding unit to supply current to a driving motor 4! for the unit. Track M and wheel 43 may serve as a ground return to complete the electrical circuit. A control switch 48 and clutch 49 enable the operator to start and stop the motor 41 and to control the movement of the welding unit 44 along edge 34 of the table.

The welding unit is provided with welding rollers and 52, at least one of which is heated in anv manner known in the art. These welding rollers are coupled to the motor 4'! so that they will be rotated in coordination with the movement of the welding unit along tracks All and 4|. Thus, the superimposed sheets of gore material 53 will remain in stationary position on table 31 while the welding unit 44 travels the length of the table and rollers 5| and 52 heatseal the layers together. These rollers are so designed that they not only seal the superimposed gores to each other but also out the surplus material away from the gores along the seam line. Details of a welding unit suitable for use in the present apparatus are described and claimed in our co-pending application Serial No. 18,584, entitled Welding Apparatus, filed of even date herewith.

As shown in Figs. 2 and 3 the gore material 53 may be laid out on the table from a suitable supply roll 54. This supply roll is rotatably carried in a U-shaped bearing 55 suspended from a traveling carriage 56. Carriage 53 is carried by overhead tracks 5'! mounted on a suitable frame 58. Thus the carriage may be moved,

longitudinally over the gore table while the material 53 is unrolled from the supply spool 54. In positioning the material 53 on the table, one edge 59 of material 53 will be aligned with the straight edge 33 of table 3!. Thus the material at the other edge will be extended beyond table edge 36 as indicated at 6%. If desired, the major portion of this extending material may be cut away by a preliminary trimming operation as indicated at 6! so that the edge of the material will correspond roughly to the shape of table edge 34. The final trimming of this edge of the gore will take place as part of the welding operation as described above.

While the apparatus described herewith involves a welding unit in which a single pair of rollers both cuts and. welds the superimposed gores, it will be clear that the cutting and welding operations might be done by separate units, if desired. Also, instead of the additional tracks 40 and 4! attached to the table frame 32, it would be possible to use the shaped table edge 34 itself as the guide for the seaming machine.

Details of assembly method The method by which the gores are assembled and for which the table described above is designed is as follows:

The first two sheets of gore material 53 are superimposed on the table as shown in Fig. 6 with one edge 59 of each sheet in alignment with the straight edge 33 of the table. A series of weights 63 is employed to hold the straight edge of the lower sheet in position and similar weights 54 hold the upper sheet in alignment. The sheets are smoothed across the table 3! so that they extend outwardly beyond edge 3 and another series of weights 55 is utilized to hold the edges in proper relation at this side of the table.

As the welding unit travels along the table the rollers 5i and 52 will both out and weld the material 53 to form a heat welded seam 66 between the first gore 25-! and the second gore 25-2. A similar seam 6'! will be formed between the extending portions 69 of the respective sheets and these portions of the material will be discarded or utilized for scrap.

After the welding operation, the gore 25-2 is pulled back toward the edge 33 of the table so that the welded joint 65 will be located above a solid portion on the table top 3i as shown in Fig. '7. In this position a reinforcing tape 67 may be applied to the seam as shown in Fig. 8. One end 68 of tape 6? is located beneath the welded seam 66 as shown and the tape then extends outwardlv from the apex end of the gores through a ring 69 and back onto the upper side of seam 65 as shown in Fig. 9. Ring 69 is carried by a strap H carried by a further ring 72 wh ch is fastened to the table frame at '54 (Figs. 2 and 4) by a suitable connecting cord or wire 13. Similar rings 59 and straps H are provided as shown in Fig. 8 for each of the gore seams to be made.

The particular tape utilized for reinforcing the seams 66 is of a pressure-sensitive type so that it may be applied to the seam readily by rolling pressure either manually or by means of a suitable machine. The tape 6'! is applied longitudinally of the seam 66 as at 19 all the way from the apex of the gores to the bottom thereof. As shown in Fig. 10, the tape extends beyond the bottom edge of the gores as indicated at 15 and is led through a holding ring 16 and turned back underneath the seam 66 as shown at .11.. Ring :lt is fastened to a strap "it which in turn is fastened to a main :tensioning ring '59 :in the same way as the straps :H 'a't'the apex of the balloon. Ring 7:9 is fastened to a cord 80 which passes over pulleys 85 (Fig. 2) and is connected to a tensioning weight 82. It will be apparent that the weight i632 will tend to stretch the tape it? and thus maintain both the welded joint to and the overlapping tape 70 under uniform tension throughout the assembly operation.

An anchor line 33 fastened to ring 79 and to an anchor ring 84 fastened to the table frame at 85 serves to limit the stretching action of weight 8.2 and thus limits the maximum elongation of the taped sea-ms it. Thus variations in the length of the tape along "the seam due to changes in atmospheric conditions during the assembly of the balloon will tend to the equalized and will not cause serious discrepancies in the lengths of the respective seams which would produce an unsymmetrical shape or wrinkles in layer of material .53 will be superimposed on gore -2. It will be noted that in the position shown, the fir t seam 66-4 is aligned with the index mark on table 31 rather than with the edge 33 of :the table. In other words, seam 56-1 has been cut to its final shape and therefore must be aligned with the tapering index 35 which corresponds to said final shape. The additional layer 53, since :it has straight edges initially, will of course be aligned with the edge 33 :of the table. Weights 63, E i, and 65 are again employed to hold the sheet 153 and gore 25-2 in position during the welding operation. :hi the course of this welding operation, the extending edges 6!! of the two layers, which project beyond edge 34 .of table .3l, will be cut-welded in the manner just described to form a second seam 68-2 between gore 25-2 and the sheet which will constitute the adjacent gore 254. This seam will be covered with tape Til-l2 in the manner described above in connection with Fig. 9.

It should be noted that in the position of the first two gores in Fig. 11 the tape 78-! is on the inside of the fold of seam 56% when the latter is ali ned with index '35. Thus application of the tape Til-1'2 to scam 56-2 in the manner previously described will result in a construction in which the tapes 18-! and iii-2 will be on the same surface of the respective gores so that in the finished balloon all the tapes may be located symmetrically on the outside of the envelope.

The process just described isrepeated with -successive sheets of material 53 and Fig. 12 illustrates schematically the arrangement .of the layers after the fourth seam 66- 1 and its reinforcing tape lo-4 have been aligned with index 35 and a further sheet of material '53 has been laid out in preparation for the cut-weldingof the next seam 5&5. The diagram shows .-clearly the manner in which the completed gores are gradually fed down into the recessed portion-38 at the center of the table where these-completed strips can be accommodated without interfer .ing with the laying-outer the .upper layers-Which rare to be welded. Thus, the material can be .fed :down into the recessed or interrupted portion .of the table 13! .in .a series of accordion-like folds without the problem .of manual handling of theparitially completed series of gores each time an additional seam is to be made.

Fig. '13 shows schematically the arrangement of the gores after 20 such gores have been united by seams '66-! to 66-!19 inclusive. At this stage of the process the main longitudina1 envelope of the balloon is substantially complete except for the trimming and joining of the straight edge '59-! of gore 25-! to the similar edge 59-213 of the last gore. To complete this final seam the leading edge lid-l is pulled up out of the recess along wall 36 as shown in Fig. 14. Enough of the material is pulled up so that seam 66-! may be aligned over index mark 35.

"Similarly, the seam Gil-l9 is aligned over the index mark and thus the two straight edges 59-l and 5940 will extend beyond the edge 3 of table 3| inposition for the cutting and welding of the final seam 66-20.

In order to facilitate the inflation of large balloons of this type, we have found it desirable to incorporate a long inflation tube 8! in the body of the balloon. This tube serves to carry the gas with which the balloon is ultimately filled up to the apex of the balloon so that the balloon can be filled uniformly from the top. The tube is subsequently withdrawn before the balloon is released. Such a tube 8i is indicated in Figs. 14, 15, and 16 and may consist of a tubular strip or hose of the same material as the balloon envelope. This tube 81 is positioned on gore 25-!3 as shown in Fig. 14 beforeseam lit-iii is pulled over into alignment with index 35. Thus, the inflation tube isreadily incorporated in the balloon before the final seam lit-2d is made and there is no problem of how to introduce such a tube longitudinally from the bottom into a completed envelope.

After seam Ski-Ell is completed, the gems will be shifted to the position of Fig. 15 so that the final tape ill-2 0 may be applied. This coinpletes the assembly of the main envelope of the balloon consisting of the longitudinal gores joined at their edges by a heat-sealed or welded seam reinforced by longitudinal tapes. This portion of the balloon in completed form is indicated 16 which also shows the general position of the inflation tube. At the apex of the balloon the gores 25 have a definite width at 83 and do not taperto a point. the balloon .is flattened on a suitable circular table 9-0 as shown in Fig. 1'7, these upper edges 88 of the respective gores will define a suitable circular opening. This opening must be sealed by a suitable cap as described below.

Similarly .at the bottom of the balloon the width of the gores at 89 is sufficient to provide a bottom opening of the desired size. The gores ,at this point will be fastened to the load bearing ring 28 in any desired manner, for example, by folding the lower ends of the gores around the ring from the inside out and then taping the folded-over portions in position.

Assembly of the cap Fig. 117. It would bepossible to provide the top of this table with suitable indieia to 1D. trimming the edges T315, positioning the cap and Thus if the upper end of fastening'the cap'in place. However, 'we' have found it preferable to provide a templet as shown in Fig. 18 which may be inserted beneath the apex of the gores for this purpose. This templet, designated generally as M, is substantially circular in form and includes a major portion 92 and a minor portion 93 hinged together along the line 94. Radial lines 95 are spaced equiangularly around the circumference of the templet to correspond to the number of gore seams in the main body of the balloon. Thus, in the illustration given there are of these radial lines 95, each of which, of course, passes through the center 96 of the templet. Since the total number of gores is an even number, obviously the corresponding radial lines at opposite sides of the tem-- plet will constitute a common diameter passing through center 93. For convenience in starting the taping operation, one of these pairs of radial lines is made heavier than the others as indicated at 91.

After the apex of the balloon is flattened on the table as shown in Fig. 17, the hinged flap 93 of the templet may be folded over to the position of Fig. 19 so that the templet may be inserted through the opening 88 and beneath the gores. For this purpose the hinged line 94 is so located on the templet that the perpendicular distance from this hinged line to the farthest point of the periphery 89 of the templet is small enough to permit insertion of the templet through the apex opening.

It will be noted from Fig. 18 that a circular index line 98 is provided on the face of the templet. This index line 98 corresponds to the desired final size of the apex opening of the balloon. Thus after the templet is positioned beneath the balloon the ends 83 of the respective gores will be trimmed along the line 98 of the templet to provide a circular top opening which is symmetrical and accurately controlled in size as shown in Fig. 20. This trimming operation will take place only after the templet has been centered beneath the apex of the balloon with the radial index lines 95 substantially aligned with the respective seams and I tapes it. While the templet is in the position of Fig. 20 and after the trimming of the apex opening, suitable index marks I M may be placed on the respective gores just outside the periphery 99 of the templet. These index marks. I9! will facilitate the alignment of the cap when the cap is subsequently placed in position above the opening. Main or starting index marks I02 may be made adjacent the seams H! which correspond to the main diametrical index line 9'! of the templet. The purpose of these main index marks is described below.

After alignment of the templet and trimming of the apex opening, a series of tapes I03 will be overlapped with their adhesive side up against the under surface of the ends 88 of the gores. Thus an annular adhesive band will be provided around the inner edge of opening 88. The templet 9| may then be removed by folding the flap 93 and pulling the templet out through the opening 68.

After removal of the templet the apex of the balloon is again flattened on the table as shown in Fig. 21 and suitable weights H14 may be located to hold the respective gores in fiat position. These weights are located with the assistance of the index marks Iiii so as to define a circular area in which the cap 2! is to be placed. This cap 21 will have a diameter corresponding to the diameter of the templet 9! so that the periphery p of the cap I05 will lie in the same relative position with respect to the apex edges 88 of the gores as did the circumference 99 of the templet.

This cap 21 is centered over the apex with the assistance of the index marks IM and the circular arrangement of' weights Hi4 and the central portion of the cap is then placed smoothly onto the upwardly facing adhesive strips I03. These strips I03 form a suitable gas-proof seal between the gores and the cap.

After this inner seal is completed, additional sealing tapes I05 are pressed down so as to overlap the outer edge I05 of the cap and hold said edge firmly against the respective gores. Thus the two bands of tape I03 and we provide a double line of attachment between the cap and the body of the balloon.

To complete the capping operation, top reinforcing strips ID'! are placed diametrically across the cap in alignment with the respective seam tapes I0. To assist the operators on opposite sides of the table in aligning the initial strip with the proper seams I0, the main index marks I02 are utilized. These marks indicate that the first tape should be positioned in line with the two seam tapes ID at opposite sides of the apex adjacent said marks. After the first reinforcing tape I0! is placed in position, additional tapes, corresponding one to each diametrically opposite pair of side seam tapes ill, are placed in position successively around the cap. These top reinforcing tapes I0! thus overlap the cap 2i and also overlap a portion of the side seams It by extending from the apex of the balloon outwardly to points I08 which are a substantial distance beyond the periphery I05 of the cap. Thus strains carried by the cap of the balloon will be transferred to the side-reinforcing tapes iii and through them to the bottom load ring previously described.

As the description indicates, this particular capping construction is readily carried out by the method indicated and is facilitated by the use of the templet 9I.

Modified balloon assembly table A modified construction for the balloon assembly table is shown in Figs. 22 and 23. In this case a pair of tables H0 and HI respectively is employed and these tables are positioned parallel to each other so that their straight edges H2 and H3 respectively are separated by a runway II4 for use of the operators. edges H5 and N6 of the respective tapes are shaped to correspond to the final gores of the desired balloon in the same manner described in connection with the single table above. Each of these tables has a recessed or interrupted central portion I09 just as in the previous case.

A suitable top frame II! (Fig. 23) is provided with tracks H8 and H9 which support the traveling carriages I20 and HM. These carriages hold the supply rolls I22 and i23 of balloon material just as in the previous case and facilitate the initial lay-out of the material on the respective tables. Tracks I24 and I25 are provided at the outer edge of the tables for a welding unit which may be identical in construction with the welding unit 44. In this modified apparatus tracks I24 and I25 are continuous and extend along each table as well as around the ends of the tables. Thus it is possible with this construction to lay out the superimposed sheets of gore material on the two tables and to run the welding unit along the table H8 in one The outer gees-nae direction and then back along the table H l in the opposite direction. Thus a continuous welding process is possible in which the operators may lay out and align the material on one table while the welding machine is forming the seam along the opposite table. This continuous proc-' ess has obvious advantages in economy of operation and is made possible by the novel arrangement of means to shift the welding roller from one table to the other. As indicated, this means is exemplified by the continuous arrangement of tracks I24 and E25 around the ends of the tables.

According to the foregoing description; a: new and improved method for manufacturing balloons has been provided in which a series of longitudinal gores are joined successively at their longitudinal edges after which the leading edge of the first gore is joined to the trailing edge of the final gore to complete the main envelope or body of the balloon. This method of assembling the balloon may include the positioning of the inflation tube prior to completion of the finalseam. Such a method is facilitated by the use of apparatus of the type described in which the assembly table has an edge shaped to correspond to the final gore of the balloon and has a recessed or interrupted central portion to accommodate the completed gores as the successive seams are made. The use of a cutting device and welding unit traveling along the gore shaped edge of the assembly table likewise offers advantages in carrying out the method of assembly by minimizing the manual handling of large pieces of gore material.

. 3 Finally, the use of a collapsible templet to facilitate the trimming and alignment of the apex of the balloon and the assembly of the balloon cap simplifies the capping operation particularly where relatively large balloons are involved.

Since various changes in the specific details of the method and apparatus will be readily apparent to persons skilled in the art, without departure from the teachings of the present specifica- 4 tion, it is intended that this invention shall in-- clude all such changes and modifications as fall within the spirit and scope of the following claims.

Now, therefore, we claim:

1. The method of successively joining adjacent thermoplastic sections of a balloon envelope which comprises the steps or": (a) arranging two of the sections in face to face relation, (1)) forming a seam between the sections by application of heat and pressure to soften and fuse the material together, (0) applying an adhesive reinforcing tape to the completed seam, (d) applying longitudinal tension to said tape and seam after said seam is complete, and (e) maintaining said longitudinal tension during subsequent formation of a similar seam between one of said first two sections and another section.

2. The method of assembling a balloon having a plurality of gores to be cut from sheets of material of uniform width and united to each other at their adjacent edges which comprises the steps of: (a) arranging two of the sheets in superimposed relation, (2)) simultaneously cutting corresponding edges of each sheet to the desired shape and uniting these edges to each other to form a seam, (c) applying longitudinal tension to the seam, after said seam is complete; and (d) successively cutting and uniting additional layers of sheet material to the remaining 10 free edges of the previously united sheets in a similar seam while maintaining at least one prior seam under tension during subsequent formation of one of said similar seams with another section.

3. The method of assembling a balloon hav ing a plurality of longitudinal gores of uniform size andshape which comprises the steps of: (a) superimposing in opposed face-to-iace relation two sheets of gore material of uniform width, (1)) cutting and uniting the sheets at one edge along a line corresponding to the desired shape of one edge of a gore, (c) similarly superimposing additional sheets'of gore material andcutting and uniting one edge of each successive gore to the remaining free edge of each preceding gore along a line corresponding to the desired gore edge shape, each successive sheet beunited to the preceding sheet before it isunited to the next following sheet, and (d) superimposingthe uncut edge of the first gore and the uncut edge of the final gore and cutting and uniting said sheets to form the final gore seam andcomplete a tubular body for the-balloon.

4. The method of forming multiple gore balloons from thermoplastic sheet material which comprises placing first and second sheets of the material in superimposed relation with the first sheet on the bottom and with a first edge of the second sheet aligned above the corresponding first edge of the first sheet parallel to the center line of a desired gore; seaming together the remaining second edges of the first and second sheets by applying heat along a line corresponding to the desired gore edge shape; shifting the newly seamed second edges toward the positiontheretofore occupied by the aligned first edges and simultaneously shifting the free first edge of the second sheet across above the line along which the second edges were seamed, thereby reversing the second sheet and also the relative locations of" the first of the second sheet; superimposing above the second sheet a third sheet having its first edge shape and thereby completing the formationandseaming of acomplete gore from the second sheet; reversing the newly seamed upper sheet and thereby reversing the relative location of its seamed and unscathed edges; successivelysuperimpo'si'ng. seaming and reversing additional sheets in like manner until the desired number of gores have been seamed; and finally superimposing and seaming together the remaining free'edgesof the first and last gores and thereby completing a tubular balloon body.

5; The method of'forrhing' multiple gore bal loons from thin, gas proofsheet material of uniform width with the aid of' a symmetrical pattern corresponding to the desired gore shape which comprises superimposing first and sec= ond' sheets of'the material on the pattern; searning together the corresponding edge of the lower sheet along a line corresponding to a first longitudinal edge of the pattern; reversing the upper sheet'on its longitudinal axis and thereby placing the newly seamed edges in alignment with the opposite longitudinal edge of the pattern and with the free edge of the sheet-extending across the first and second edges:

one edge of the upper sheet and pattern edge; superimposing a third sheet above the pattern and second sheet; seaming together one edge of the third sheet and the corresponding free edge of the second sheet along the first pattern edge; similarly reversing the third sheet; successively superimposing, seaming and reversing additional sheets in like manner until the desired number of gores have been joined; and finally superimposing and seaming the remaining free edges of the first and last sheets and thereby completing a tubular balloon body.

6. The method of forming multiple gore balloons from thin, gas proof sheet material of uniform width with the aid of a symmetrical pattern corresponding to the desired gore shape which comprises superimposing first and second sheets of the material on the pattern; seaming together one edge of the upper sheet and the corresponding edge of the lower sheet along a line corresponding to a first edge of the pattern; reversing the upper sheet and thereby placing the newly seamed edges in alignment with the opposite edge of the pattern and with the free edge of the sheet extending across the first pattern edge; superimposing a third sheet above the pattern and second sheet; seaming together one edge of the third sheet and the corresponding free edge of the second sheet along the first pattern edge; similarly reversing the third sheet; successively superimposing, seaming and reversing additional sheets in like manher until the desired number of gores have been joined; and finally superimposing and seaming the remaining free edges of the first and last sheets and thereby completing a tubular balloon body.

7. The method of forming multiple gore balloons from thin, gas proof sheet material of uniform width with the aid of a symmetrical pattern corresponding to the desired gore shape which comprises superimposing first and second sheets of the material on the pattern; seaming together one edge of the upper sheet and the corresponding edge of the lower sheet along a line corresponding to an edge of the pattern; superimposing a third sheet above the second; seaming together one edge of the third sheet and the remaining free edge of the second along a line corresponding to an edge of the pattern, superimposing additional sheets and seaming together one edge of each successive sheet and the remaining free edge of the preceding sheet before the next succeeding sheet is superimposed, until the desired number of gores have been joined; and finally superimposing and seaming together the remaining free edges of the first and last sheets and thereby completing a tubular balloon body.

8. The method of forming multiple gore balloons from thin, gas prooi sheet material of uniform width with the aid of a symmetrical pattern corresponding to the desired gore shape which comprises superimposing first and second sheets of the material on the pattern; seaming together one edge of the upper sheet and the corresponding edge of the lower sheet along a line corresponding to an edge of the pattern; superimposing a third sheet above the second; seaming together one edge of the third sheet and the remaining free edge of the second along a line corresponding to an edge of the pattern, and superimposing additional sheets and seaming together one edge of each successive sheet and the remaining free edge of the preceding sheet before the next succeeding sheet is superimposed, until the desired number of gores have been joined.

9. The method of forming multiple gore bal loons from thin, gas proof sheet material of uniform width with the aid of a symmetrical pattern corresponding to the desired gore shape which comprises superimposing first and second sheets of the material on the pattern; seaming together one edge of the upper sheet and the corresponding edge of the lower sheet along a line corresponding to an edge of the pattern; superimposing a third sheet above the second; seaming together one edge of the third sheet and the remaining free edge of the second along a line corresponding to an edge of the pattern, superimposing additional sheets and seaming together one edge of each successive sheet and the remaining free edge of the preceding sheet before the next succeeding sheet is superimposed, until the desired number of gores have been joined; superimposing a longitudinally extending inflation tube on the final upper sheet, with the tube projecting beyond one end of the pattern; pulling the free edge of the bottom sheet up along the edges of the sheets at the side opposite the free edge of the upper sheet and across the upper sheet and inflation tube, and finally superimposing and seaming together the remaining free edges of the first and last sheets and thereby completing a tubular balloon body with an inflation tube axially enclosed therein.

10. The method of forming multiple gore balloons from thin gas proof sheet material of uniform width with the aid of a table having thereon a symmetrical gore pattern narrower than said Width and also having guide means thereon outside one edge of the pattern for alignment of one edge of the sheet material parallel to the axis of symmetry of the gore and with the material completely covering the gore pattern, which comprises: superimposing first lower and second upper sheets on the pattern, with one edge of each sheet aligned with the guide means; seaming together the other edges of the two sheets along one edge of the pattern; reversing the second sheet on the axis of symmetry of the gore and aligning the newly seamed edges with the opposite edge of the pattern, while the remainder of the second sheet completely covers the pattern; superimposing a third sheet, with one edge aligned with the guide means; seaming together an edge of the third sheet and the remaining free edge of the second sheet along said one edge of the pattern; reversing the third sheet and aligning its newly seamed edge with said opposite edge of the pattern; and thereafter successively superimposing and seaming additional sheets until the desired number of gores have been joined, each successive sheet, after being seamed to the preceding sheet, being reversed and aligned in like manner before the following sheet is superimposed.

11. The method of forming multiple gore balloons from thin gas proof sheet material of uniform width with the aid of a table having thereon a symmetrical gore pattern narrower than said width and also having guide means thereon outside one edge of the pattern for alignment of one edge of the sheet material parallel to the axis of symmetry of the gore and with the material completely covering the gore pattern, which comprises; superimposing first lower and second upper sheets on the pattern, with one edge of each sheet aligned with the guide means; seaming together the other edges of the two sheets along the edge of the pattern farthest from the guide means; reversing the second sheet on the axis of symmetry of the gore and aligning the newly seamed edges with the edge of the pattern nearest the guide means, while the remainder of the second sheet completely covers the pattern; superimposing a third sheet, with one edge aligned with the guide means; seaming together the op posite edge of the third sheet and the remaining free edge of the second sheet along said edge of the pattern farthest from the guide means; reversing the third sheet and aligning its newly seamed edge with said edge of the pattern nearest the guide means; and thereafter successively superimposing and seaming additional sheets until the desired number of gores have been joined, each successive sheet, after being seamed to the preceding sheet, being reversed and aligned in like manner before the following sheet is superimposed.

12. The method of forming multiple gore balloons from thin gas-proof sheet material which comprises placing first and second sheets of the material in superimposed relation with the first sheet on the bottom and with a first edge of the second sheet aligned above the corresponding first edge of the first sheet parallel to the center line of a desired gore; seaming together the remaining second edges of the first and second sheets along a line corresponding to the desired gore edge shape; shifting the newly seamed second edges toward the position theretofore occupied by the aligned first edges and simultaneously shifting the free first edge of the second sheet across above the line along which the second edges were seamed, thereby reversing the second sheet and also the relative locations of the first and second edges of the second sheet; superimposing above the second sheet a third sheet having its first edge aligned generally above the original line of alignment of the first edges of the first two sheets; seaming together the superimposed second edge of the third sheet and the first edge of the second sheet along a line corresponding to the desired gore edge shape and thereby completing the formation and seaming of a complete gore from the second sheet; reversing the newly seamed upper sheet and thereby reversing the relative location of its seamed and unseamed edges; successively superimposing, seaming and reversing additional sheets in like manner until the desired number of gores have been seamed;

and finally superimposing and seaming together the remaining free edges of the first and last gores and thereby completing a tubular balloon body.

13. The method of forming multiple gore balloons from thin gas-proof sheet material which comprises superimposing first and second sheets of the material; seaming together a first longitudinal edge of the second sheet and the corresponding edge of the first sheet along a line corresponding to the desired gore edge shape; shifting the second longitudinal edge of the second sheet across the longitudinal axis of the sheet toward the line along which the first edges were seamed, thereby at least partially reversing the second sheet; superimposing a third sheet above the second sheet; seaming together the superimposed first edge of the third sheet and the second edge of the second sheet along a line corresponding to the desired gore edge shape, thereby complet- 14 ing the formation and seaming of a complete gore from the second sheet; shifting the second edge of the third sheet across the longitudinal axis of the sheet and thereby at least partially reversing the third sheet; successively superimposing, seaming, and at least partially reversing additional sheets in like manner until the desired,

number of gores have been joined; and finally superimposing and seaming together the remaining free edges of the first and last gores, thereby completing a tubular balloon body.

14. The method of forming multiple gore balloons from thin gas-proof sheet material which comprises superimposing a plurality of sheets of said material, seaming together one edge of the first sheet and the corresponding edge of the second sheet along a line corresponding to the desired gore edge shape, shifting the newly seamed edges of the first and second sheets toward the opposite edge of the gore, similarly seaming together one edge of each successive sheet and the remaining free edge of the preceding sheet and shifting each set of seamed edges toward the opposite edge of the gore before the next edges are seamed, and finally seaming together the remaining free edges of the first and last sheets along a line corresponding to the desired gore edge shape and thereby completing a balloon body portion.

15. The method of forming multiple gore balloons from thin gas-proof sheet material which comprises superimposing a plurality of sheets of said material, seaming together one edge of the first sheet and the corresponding edge of the second sheet along a line corresponding to the desired gore edge shape, similarly seaming together one edge of each successive sheet and the remaining free edge of the preceding sheet, and finally superimposing and seaming together the remaining free edges of the first and last sheets along a line corresponding to the desired gore edge shape and thereby completing a balloon body portion.

FRANK J. LA MERE. KERMIT F. J OI-llNSON. OTTO C. WINZEN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,081,792 Vaniman Dec. 16, 1913 1,198,258 Naylor Sept. 12, 1916 1,820,124 Dorogi Aug. 25, 1931 2,140,117 Salfisberg Dec. 13, 1938 2,232,640 Schwartzman Feb. 18, 1941 2,281,976 Hansen May 5, 1942 2,305,010 Kenney Dec. 15, 1942 2,317,925 Lewis Apr. 27, 1943 2,341,399 Timblin Feb. 8, 1944 2,351,350 Mallory June 13, 1944 2,373,744 Coghill 'Apr. 17, 1945 2,379,311 Martin June 26, 1945 2,444,150 Best June 29, 1948 2,478,121 Morner Aug. 2, 1949 2,489,210 Weeks Nov. 22, 1949 2,496,911 Green Feb. 7, 1950 2,530,221 Bender Nov. 14, 1950 

1. THE METHOD OF SUCCESSIVELY JOINING ADJACENT THERMOPLASTIC SECTIONS OF A BALLOON ENVELOPE WHICH COMPRISES THE STEPS OF: (A) ARRANGING TWO OF THE SECTIONS IN FACE TO FACE RELATION, (B) FORMING A SEAM BETWEEN THE SECTIONS BY APPLICATION OF HEAT AND PRESSURE TO SOFTEN AND FUSE THE MATERIAL TOGETHER, (C) APPLYING AN ADHESIVE REINFORCING TAPE TO THE COMPLETED SEAM, (D) APPLYING LONGITUDINAL TENSION TO SAID TAPE AND SEAM AFTER SAID SEAM IS COMPLETE, AND (E) MAINTAINING SAID LONGITUDINAL TENSION DURING SUBSEQUENT FORMATION OF A SIMILAR SEAM BETWEEN ONE OF ACID FIRST TWO SECTIONS AND ANOTHER SECTION. 